The invention relates generally to a dermal barrier composition, a protective layer for skin, a method for manufacturing the dermal barrier composition, a method for protecting skin tissue, and a method of holding active ingredients in close proximity to skin.
The need for a protective hand lotion that not only provides protection against deleterious chemicals but also acts as an active antimicrobial and antiviral barrier has long been known in industries such as health care and food handling. In the health care industry, such a hand lotion would reduce the incidence of nosocomial infection transmission; not only between patients, but also between patient and staff. In the food handling industry, there has been an increasing awareness of food borne pathogens, both among manufacturers and the general public.
Vinyl gloves are often used to provide a level of protection against chemical and pathogenic substances. This level of protection is often less than optimal. The gloves serve to increase perspiration rate, which provides a rich medium for growth and proliferation of surface pathogens. Further, new gloves typically have a defect incidence rate as high as 50 to 96 percent. The combination of these two factors means that pathogens are inoculated through defects in the gloves to contacted materials or patients at much higher levels than if no protection was used at all.
Work practices to date have identified frequent handwashing as the most effective tool at reducing pathogenic transfer or inoculation. Unfortunately, frequent handwashing leads to increased resistance by employees, as frequent exposure to water and detergents results in de-lipidation of the dermal structures with resultant chaffing and painful contact dermatitis. While studies have shown that the use of emollient creams and lotions reduce these effects, such creams and lotions can require frequent application because they are easily washed off.
In addition to protection against pathogenic invaders, there is also a need for protection against a wide range of chemicals. These can range from substances which are locally damaging to dermal structures, such as caustic materials, to substances which are known to be absorbed through the dermis. Such materials can result in metabolic as well as mutagenic damage. A wide range of industries exhibit a need for protection against such chemicals. These include, for example, hair salons, where employees are subjected to caustic materials and dyes. A number of different industries utilize various hydrocarbons in manufacturing processes. Food processing industries subject employees to various herbicides, insecticides and fertilizers.
Antimicrobial barrier compositions for use on human skin are described, for example, in U.S. Pat. Nos. 5,336,305 and 5,417,968 to Staats. Hui et al, U.S. Pat. No. 5,082,656; and Smith, U.S. Pat. Nos. 5,658,559 and 5,874,074 also describe compositions for topical application.
A dermal barrier composition for topical application is provided by the invention. The dermal barrier composition includes a hydrophilic polymer emulsion and a hydrophobic polymer emulsion.
The hydrophilic polymer emulsion includes poly (methyl vinyl ether/maleic acid), poly (vinyl pyrrolidone/1-eicosene), and poly (vinyl pyrrolidone/1-hexadecene). The poly (methyl vinyl ether/maleic acid) is present in the hydrophilic polymer emulsion in an amount greater than either the poly (vinyl pyrrolidone/1-eicosene) or poly (vinyl pyrrolidone/1-hexadecene). The hydrophobic polymer emulsion includes poly (vinyl pyrrolidone/1-hexadecene), poly (vinyl pyrrolidone/1-eicosene), and poly (methyl vinyl ether/maleic acid). The poly (vinyl pyrrolidone/1-hexadecene) is present in the hydrophobic polymer emulsion in an amount greater than either the poly (vinyl pyrrolidone/1-eicosene) or poly (methyl vinyl ether/maleic acid). The emulsion may be formed as a viscous fluid that may be applied by hand, or alternatively by a spray or aerosol. Active components, such as biocides, become physically distributed in voids throughout the applied composition and remain efficacious during the period of protection.
The invention is found in a dermal barrier composition having a hydrophilic polymer emulsion and a hydrophobic polymer emulsion as described above in a ratio of about 1 to 1.
The invention is also found in a dermal barrier composition having a hydrophobic polymer emulsion and a hydrophobic polymer emulsion as previously described in a ratio of about 2.5 to 1. Both such compositions form barriers which block contact by harsh or toxic materials from the skin for appreciable time periods in a workplace environment, without inhibiting natural excretion of fluids from the skin.
The invention is also found in a dermal barrier layer including a dermal barrier composition prepared by mixing a hydrophilic polymer emulsion and a hydrophobic polymer emulsion; wherein the dermal barrier emulsion, when applied to dry fritted glass in a thickness of about 0.5 to about 0.85 millimeters and allowed to bond to said glass for a period of 30 seconds, provides a film which remains at least about 80 percent adhered to the fritted glass after treatment with a 5% ammonium hydroxide for a period of 3 hours. When applied to the skin, the barrier strongly adheres to the stratum corneum and thereafter depletes only slowly.
Other aspects of the invention include methods of making dermal barrier compositions as previously described, which optionally can include encapsulated active agents such as biocides, fungicides, sun screens and insect repellents.
The invention is found in a method for protecting skin tissue against excessive moisture loss, said method including the steps of washing skin tissue to form cleansed skin tissue, and contacting said cleansed skin tissue with the dermal barrier emulsion described above.
The invention is found in a method of carrying and holding an active agent in proximity to skin tissue, the method including the steps of washing skin tissue to form cleansed skin tissue, and contacting the cleansed skin tissue with the dermal barrier emulsion described above.
Another feature in accordance with the invention is that the film forms a protective barrier that is comparable with the body""s need to excrete liquids from the skin, while blocking access to higher molecular weight materials from the workplace environment. This results from the fact that the barrier is physically integral except for distributed micro-openings of irregular outline which permit this anistropic function to exist. Protective properties which last for hours in use, and which meet or exceed the properties of protective gloves are thus provided with greater convenience and comfort than gloves.